Alcohol, Other Drugs & Driving

Drinking alcohol and then driving is very dangerous and a serious problem. People who drink alcohol are involved in traffic accidents resulting in over 20,000 deaths every year. Alcohol impairs muscle coordination, reaction time, depth perception, and night vision. It also affects the parts of the brain that control judgment and inhibition. For some people, one drink is all it takes to show signs of impairment.

How Alcohol Works. Alcohol goes directly into the blood stream and is carried to the brain. After passing through the brain, a small percentage is removed in urine, perspiration, and by breathing, while the rest is carried to the liver. The liver can only process one-third an ounce of alcohol per hour, which is considerably less than the alcohol in a standard drink. This is a fixed rate, so only time, not black coffee or a cold shower, will sober you up. If you have drinks faster than your body can get rid of them, you will have more alcohol in your body, and your driving will be more affected. The Blood Alcohol Concentration (BAC) commonly measures the amount of alcohol in your body. See Figure 2.22 at the bottom of this page.

All of the following drinks contain the same amount of alcohol:

A 12-ounce glass of 5% beer.

A 5-ounce glass of 12% wine.

A 1 ½-ounce shot of 80 proof liquor.

What Determines Blood Alcohol Concentration? BAC is determined by the amount of alcohol you drink (more alcohol means higher BAC), how fast you drink (faster drinking means higher BAC), and your weight (a small person doesn’t have to drink as much to reach the same BAC).

Alcohol and the Brain. Alcohol affects more and more of the brain as BAC builds up. The first part of the brain affected controls judgment and self-control. One of the bad things about this is it can keep drinkers from knowing they are getting drunk. And, of course, good judgment and self-control are absolutely necessary for safe driving.

As BAC continues to build up, muscle control, vision, and coordination are affected more and more. Effects on driving may include:

Straddling lanes.

Quick, jerky starts.

Not signaling, failure to use lights.

Running stop signs and red lights.

Improper passing.

See Figure 2.23.

These effects mean increased chances of a crash and chances of losing your driver’s license. Accident statistics show that the chance of a crash is much greater for drivers who have been drinking than for drivers who have not.

Besides alcohol, other legal and illegal drugs are being used more often. Laws prohibit possession or use of many drugs while on duty. They prohibit being under the influence of any “controlled substance,” amphetamines (including “pep pills,” “uppers,” and “bennies”), narcotics, or any other substance, which can make the driver unsafe. This could include a variety of prescription and over-the-counter drugs (cold medicines), which may make the driver drowsy or otherwise affect safe driving ability. However, possession and use of a drug given to a driver by a doctor is permitted if the doctor informs the driver that it will not affect safe driving ability.

Don’t use any drug that hides fatigue–the only cure for fatigue is rest. Alcohol can make the effects of other drugs much worse. The safest rule is don’t mix drugs with driving at all.

Use of drugs can lead to traffic accidents resulting in death, injury, and property damage. Furthermore, it can lead to arrest, fines, and jail sentences. It can also mean the end of a person’s driving career.

Figure 2.22

What Is a Drink?

It is the alcohol in drinks that affects human performance. It doesn’t make any difference whether that alcohol comes from “a couple of beers,” or from two glasses of wine, or two shots of hard liquor. Approximate Blood Alcohol Content

Drinks

Body Weight in Pounds

Effects

100

120

140

160

180

200

220

240

0

.00

.00

.00

.00

.00

.00

.00

.00

Only Safe
Driving Limit

1

.04

.03

.03

.02

.02

.02

.02

.02

Impairment
Begins

2

.08

.06

.05

.05

.04

.04

.03

.03

Driving Skills
Significantly
Affected –

Criminal Penalties

3

.11

.09

.08

.07

.06

.06

.05

.05

4

.15

.12

.11

.09

.08

.08

.07

.06

5

.19

.16

.13

.12

.11

.09

.09

.08

6

.23

.19

.16

.14

.13

.11

.10

.09

7

.26

.22

.19

.16

.15

.13

.12

.11

Legally
Intoxicated –

Criminal Penalties

8

.30

.25

.21

.19

.17

.15

.14

.13

9

.34

.28

.24

.21

.19

.17

.15

.14

10

.38

.31

.27

.23

.21

.19

.17

.16

Subtract .01% for each 40 minutes of drinking. One drink is 1.5 oz. of 80 proof liquor, 12 oz. of beer, or 5 oz. of table wine.

Figure 2.23

Effects Of Increasing
Blood Alcohol Content (BAC)

Blood Alcohol Content is the amount of alcohol in your blood recorded in milligrams of alcohol per 100 milliliters of blood. Your BAC depends on the amount of blood (which increases with weight) and the amount of alcohol you consume over time (how fast you drink). The faster you drink, the higher your BAC, as the liver can only handle about one drink per hour—the rest builds up in your blood.

BAC

Effects on Body

Effects on
Driving Condition

.02

Mellow feeling, slight body warmth.

Less inhibited.

.05

Noticeable relaxation.

Less alert, less self-focused, coordination impairment begins.

.08

Definite impairment in coordination & judgment .

Drunk driving limit, impaired coordination & judgment.

.10*

Noisy, possible embarrassing behavior,
mood swings.

Reduction in reaction time.

.15

Impaired balance & movement, clearly drunk.

Unable to drive.

.30

Many lose consciousness.

.40

Most lose consciousness, some die.

.50

Breathing stops, many die.

BAC of .10 means that 1/10 of 1% (or 1/1000) of your total blood content is alcohol.

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